Three-Quarters Curiosity
by Tallulah99
Summary: Curiosity has always been the driving force in the life of Sherlock Holmes. Tonight it drives him to embark on a potential experiment that means working with volatile elements and potentially explosive results...and Molly Hooper. Written for the '50 Reasons to Have (Sherlolly) Sex' meme on tumblr. Sherlolly. Rated M for a reason.


"Love is three-quarters curiosity" - Giacomo Casanova

* * *

The driving force in the life of Sherlock Holmes had always been curiosity. He was compelled by his need for facts, for information, for understanding the 'why' and the 'how' of the thing. As a child he had first asked questions and then read books, then researched and learned to experiment. In a world that offered a nearly infinite number of ways to indulge in carnal desire, he had found nothing that eclipsed the visceral satisfaction of sated curiosity.

There was passion inherent in the act of discovery, a drive to attain new information and assimilate facts into answerable equations. Why else did man explore? Why else study and theorize? Curiosity was the desire of the mind - the need to understand, to solve for the unknown variable, to replace the vacuum of ignorance with empirical truth.

Tonight, however, curiosity burned.

Sherlock sat in his usual spot in the back of the lab with his fingers tented against his lips, wrestling with the possible ramifications of a potential experiment.

This particular experiment had long been a source of interest for him, but it meant working with volatile elements and risking dangerous, possibly explosive, results. Curious he may be, but he was not foolhardy, and the risks were not insignificant. For many months the tantalizing lure of the unknown had been mitigated by reluctant caution.

The desire to discover had not gone away, however. In fact, it had grown exponentially as time passed until it was a near constant source of discomfort. Dangerous it may be, but he thought he must undertake this particular experiment or be consumed himself.

It was late. The regular hospital day-shift had all gone home hours ago. The labs were quiet and deserted now and would remain so until morning. The only ones who might be on the floor at this time of night were Sherlock himself and -

Molly Hooper pushed the swinging door open with her shoulder, her sneakers squeaking on the painted concrete floor.

She was wearing her lab coat, but it hung open over her regular street clothes - no postmortems pending in the morgue then. That was good. He was going to need her undivided attention for a while tonight. She wore her long, dark hair pulled up off of her neck and secured in a ponytail on the back of her head. It was the simple, easy style that she adopted whenever she was going to be working alone during the graveyard shift. That was good too. He quite liked looking at Molly's neck.

She didn't notice him at first, preoccupied as she was by the contents of the clipboard that she carried in front of her like the bowsprit of a ship. When she glanced up and saw him sitting silently in the back of the room, she jumped and her clipboard clattered to the floor.

"Oh, Sherlock!" she exclaimed and then gave a nervous laugh as she bent to retrieve her work. "I didn't know you were going to be here tonight."

"Nor did I," he said, watching her fluttery, bird-like movements with interest. He had been aware of her apparent attraction to him for many years, but he hadn't given it much thought before tonight. Now he observed her carefully, searching for the tell-tale, physiological evidence of her continuing infatuation with him.

The eyes were key. Hers were mildly dilated - much more so than the bright lights of the lab would seem to allow for. She also had a difficult time maintaining direct eye contact; her gaze darted away after little more than a second. She was fidgeting as thought she were hyperaware of her body but uncertain as to what to do with it. And then she bit her lower lip, and Sherlock felt a slow smile spread across his face.

Excellent.

"What is it?" she asked, suddenly anxious under his scrutiny. "Do I have something on my face?" She brushed a self-conscious hand across her lips, and gave him a questioning look.

"No, no," he assured her as he pushed away from the table and unfolded himself from his seat. "You look fine. Quite nice in fact."

She blinked at him in surprise. "I - I do?"

"Yes, of course," he said.

Sherlock was already finding this experiment very edifying. He felt warm, and his own breathing rate had increased. Physiological evidence, indeed.

He came around to the front of the table and leaned against it, facing her with his arms crossed over his chest. He had worn the dark plum-coloured shirt that she favoured, and slim-fitting black trousers that flattered his lean frame.

She liked the way he looked. He knew that she did. So he put himself on display for her benefit. This particular variable was neither crucial, nor required for the sake of the experiment, but her reaction to his appearance was well worth the extra effort.

She swallowed hard and her grip tightened on her clipboard until her knuckles whitened.

"What's going on, Sherlock?" she asked, and he was gratified by the breathless quality in her voice.

"Nothing," he said, and then his voice dropped an octave. "Not yet, anyway."

"Wh-what do you mean?"

She was anxious. Her eyes were wide and he could see the rapid beat of her pulse in the hollow of her throat.

This was a critical moment. Her emotions would be heightened by the adrenaline rush that stimulated a fight or flight response. It wouldn't take much to scare her away. Embarrass or antagonize her and she would be a white blur, leaving nothing behind but the sweet smell of her shampoo and an ever more demanding need.

"There is a project that I require your assistance with. Are you very busy tonight?"

The lines of her shoulders relaxed a degree. This was familiar territory between them. "Yes - I mean - no. No, I'm not very busy tonight. I have some paperwork to file, but that can -"

"Good," he interrupted. He was surprisingly impatient to be under way. He gestured toward the table at the back of the room where he habitually worked. "If you wouldn't mind?"

Molly's comfort level had returned he was pleased to note. There was no sign of anxiety in her now.

Her ponytail brushed the collar of her lab coat as she went past him and he couldn't help but notice the elegant line of her neck, or the tiny strawberry-shaped birthmark just above the neckline of her shirt.

_Just_ _there_ he thought, and took a deep, shuddering breath.

"So, what are you working on?"

Sherlock could well understand her puzzled tone of voice. His customary work space was immaculately clean. Where there were usually stacks of research journals or pilfered lab equipment scattered across the surface, tonight there was nothing.

"Did you need me to - oh!" She turned and startled at his proximity. He was invading her personal space very deliberately, crowding her between his body and the table. Reflexively, she tried to take a step backwards and collided with the edge. Her eyes went wide.

She wasn't trapped. He had purposely given her room to escape to either side. It was not his intention to intimidate her. He was merely standing closer to her than he usually did to anyone if he could help it. It was a simple test to initiate the rest of the experiment - in a stimulus response situation, would Molly Hooper stay or bolt?

In the near silence of the lab, her breathing sounded laboured. She was looking up at him with dark eyes creased in uncertainty, but she did not try to move away.

"Sh-sherlock?"

He looked down at her, feeling oddly out of breath himself. His chest felt tight. The warmth he felt had spread though his body until he felt almost feverish. "I am curious, Molly."

She swallowed. "About what?"

His full lips curled slowly upwards into a provocative smile. "You."

She drew in a breath that was almost a gasp, and he saw her eyes flick towards her path of escape, but she stayed her ground.

"But, why would you be curious about _me_?"

"It is my nature to be curious," he replied. He caught the tip of his tongue between his teeth and saw her breath catch. How lovely. "And there are still many things that I don't know about you."

There was a moment of perfect stillness as they both waited for her to ask the next logical question.

"Like what?" she asked, softly.

"Oh, so many things," he said. His tone was airy, but his eyes glittered as he moved closer to her, erasing the remaining space between them in a single step. He was looming over her now, but not to frighten her. This was the commencement of an experiment he had been looking forward to for a long, long time - desire of the flesh beget by curiosity of the mind. "I want to know how you taste when you're aroused, Molly." He ghosted his fingertips down the curve of her cheek and felt a rush of pleasure when she shivered beneath his touch. "I want to know what sort of sounds you make when I move inside you. And, most of all, I want to know what you're going to look like when I make you come."

"When - what?" It wasn't quite a cry. She didn't seem to have the breath left in her to manage more than a hoarse whisper.

Sherlock arched a dark brow at her. "You prefer the term 'orgasm'?"

"I - I don't know." Her pale cheeks flamed pink. "What are we talking about, Sherlock?"

He gave her a mildly censorious look. "Now, now, Molly," he chided. "Don't be deliberately obtuse. You know exactly what I'm talking about." He traced her lips gently with his thumb, noting with satisfaction how her eyes fluttered closed and her warm breath stuttered against his hand.

Sherlock was curious, and even more so than he had admitted to her. There were so very many things that he wanted to discover about Molly Hooper - things that he had spent years thinking about when he was alone in the dark - hypothesizing, theorizing. Now, he wanted to _know_. His curiosity would no longer tolerate delay. He wanted to know what she would look like with her lips red and swollen from his kisses. He wanted to see for himself the exact shade of her nipples and to know just how they felt pebbled against his tongue. He wanted to know the shape of her body, and to feel it, hot and slick, and moving beneath him. But more than anything, more than even his next breath, he wanted to know what it would take to make the shy little pathologist lose control and pulse around him while she cried his name.

And Sherlock Holmes was _impatient_. He wanted to know _now_.

His body was pinning her to the edge of table now, and he knew she could feel him, hard against her hip. Her eyes were still closed. He slid his hand to the back of her head, and felt the thundering of his heart in his chest as he leaned down and placed a gentle kiss over the strawberry-shaped birthmark on the curve of her neck.

Her skin was warm and smelled of clean skin and soap and _Molly_. Want shot through him like a lightening bolt and he moved against her, reveling in the delicious pressure of her body. He moaned softly.

When he straightened, she was looking up at him with heavy-lidded eyes.

"Are you going to kiss me now?"

He nodded, a short jerk of his chin and her lips curled up into a smile.

"Good."

He bent his head and kissed her lips. Molly kissed him back.

Sherlock was not a virgin. It amused him that so many people assumed that he must be. His innate desire for sensory information - the same compulsion that had first drawn him over the precipice and into the world of drug addiction - had demanded that he indulge that curiosity at the tender age of fifteen. It had not been worth the social effort it would have required to bother with seduction, so he had simply sought out a reputable brothel and sated both the need to know as well as the overpowering sexual desire of a teenage boy.

Kissing was another matter altogether. Despite the popular misconception, most prostitutes would kiss a client, if the client so desired, but as it was unnecessary to his purposes, Sherlock had not bothered much with that particular aspect of physical intimacy.

With Molly's lips pressed to his, he couldn't help but wonder if he had been focused on the wrong part of the equation.

She was delicious - sweet and soft and warm, and the desire to _have_ her, to consume her with his hands and mouth and body, tore through him in a wave that took him entirely by surprise. His fingers tightened and his hips flexed instinctively, pressing his erection hard into the gentle swell of her hip. He kissed her again, harder, forcing her lips apart so the he could taste her mouth with his tongue. She opened under him and met his tongue with dainty, pointed strokes of her own. He heard a low sound that was nearly a growl, and realized it was him.

Sherlock had never known a rush of such violent, physical need in his life. It was overwhelming and chaotic, and part of him was desperate to push away, to distance himself from the flood of sensory input, but he didn't. Instead he clung to her, bruising her lips and crushing her body to him. He blocked out everything else so that he could drown in Molly Hooper.

He wanted to touch her. Without relinquishing her lips, he pushed the lab coat off of her shoulders. She helped, arching her back so he could strip it off of her arms, and then it was a puddle on the ground at their feet. He put his hands on her hips and lifted her to the surface of the table and stood between her knees.

He kissed her again - hard, harder, hardest. When she reached up and threaded her fingers through the curls at the base of his skull, he gently bit her lip and she gasped.

He broke away from her lips and kissed her shoulder again, touching his tongue to the birthmark on her neck. Her quiet moan was a subterranean vibration that he felt everywhere their bodies touched.

What had started as a clinical desire for information was spiraling into something far wilder and more uncontrollable than he had intended. This was no simple experiment. There would be no facts or empirical data to collate and consider when all was said and done. There was only the sense and sensation of the moment, and the grateful surrender of control like a self-indulgent drug-addict on a binge.

Slowly, Sherlock skated his hands up her sides. He could feel the bump of each individual rib as it slid past beneath his fingertips. Her blouse was suddenly too much, too impeding, too _there_. He yanked it up, too impatient to touch her to consider stopping to bother with the buttons just yet. His hands slipped under the loose fabric and gently, reverently, shuddering, he caressed the tender skin just above her waist.

His long fingers brushed across her belly, his thumbs tracing light circles, raising goose flesh that made her shiver and hum softly in his ear.

Her skin was as soft and heated as he had anticipated - hoped - known - it would be. And now he wanted to see her.

He lifted his head and kissed her again, tracing her lips with his tongue before he took her mouth. With his eyes closed, he felt for the row of pearl buttons that ran down the front of her blouse. He undid them one at a time, letting his fingers trail delicately down the bare line of her chest as he slowly uncovered her.

When he felt the fabric part and fall away, he reached for her, cupping his hands on either side of her face before he pulled back with his eyes still closed. He tormented himself for a moment longer, listening to the gentle harmony of their matched breathing before he allowed himself to open his eyes.

When he did, he met her gaze immediately. Her eyes were half-closed, but sparkling and her lips were reddened with hard use. He felt an unfamiliar surge of possessive, animalistic triumph at the sight. Where he would usually have pushed the sensation away in disgust, tonight he reveled in the carnality. Those were his marks on her. _He_ had brought her to his state of arousal - him, and no one else.

He could tell she was watching his face as he continued undressing her, but she said nothing as he slid the silky fabric off of her shoulders, and she only shivered when he worked her second hand free and then brought it up to kiss the palm before releasing her.

Her eyes narrowed as she examined him, and then her lips curved into a slow smile. It wasn't the quick flash of uncertainty that he was used to seeing on her either, but the honest, self-satisfied expression of a woman who has searched a man's face and found true desire there.

"Well, what are you waiting for?" she said. Her voice was low and breathy. "Touch me."

There was no chance of resisting. He managed to tamp down the wildness of the urge for fear that he would be too rough and hurt her, but he wouldn't have been able to keep his hands off of her now if his life had depended on it.

Sherlock had never thought much about his hands. They were large and capable, and he had trained them to be precision instruments in regard to his work, but the years of frequent abuse had left them rough and calloused, and he winced as they slid across Molly's delicate skin. In an unconscious act of restitution, he followed the path of his fingers with his lips, kissing her throat, the side of her neck, the indentation behind her ear, the curve of her shoulder. Then, at last, he let his hands fall to the curve of her breasts. He cupped them gently in his palms and brushed his thumbs over the satin covered peaks, inhaling sharply when she moaned and pressed harder into his touch.

He wanted to see her - all of her - _now_.

He kissed her again, exploring her mouth with this tongue as he reached for the clasp of her bra. He felt a momentary flash of uncertainty when he brushed over it. Deft fingers he might have, but the intricate workings of a woman's lingerie were somewhat outside his usual purview.

Sensing his hesitation, or perhaps simply anxious herself, Molly reached behind her back with one hand and unhooked the garment with a flick of her fingers. The taut line of fabric relaxed, but then she leaned back on her hands, tacitly leaving the honors to him. The barest hint of a smug smile played around the edges of her lips and she regarding him with sparkling eyes and a brow arched in challenge.

It was a glorious torture to force himself to move slowly. He drew ancient symbols on the delicate skin above her breasts with the tips of his fingers. They were 'woman' and 'glory' and 'passion' and they seemed to belong on her body.

With one finger, he dragged the satin strap of her bra to the curve of her shoulder until it crested the slope and fell into the crease of her elbow. Then he did the same to the opposite side, only this time, when the strap fell, gravity won out and her bra fell away, baring her breasts completely. Sherlock sucked in a breath and said a silent word of appreciation for the laws of Newton.

He remembered once making a disparaging comment regarding the size of Molly's breasts. He knew that, at the time, he had suggested that they were too small, but right now he could not for the life of him remember why. They were full and perfectly shaped and came to a small, upturned point.

He reached for her, skimming his fingertips across the line of her clavicle and then downwards with the slightest amount of friction, barely touching her until the pad of his finger brushed across the pale pink tip of one breast. Molly arched her back and hummed deep in her throat. Her eyes were closed and her lips were parted and he wanted to devour her. He leaned forward and breathed her scent into his lungs like a drug. Then he caught her wrist in his hand, as much to anchor himself as to hold her, and took her nipple into his mouth.

Her moan was soft and breathless, and satisfaction poured into his veins like warm honey.

His hand was on her wrist, his mouth on her breast and he was harder than he could ever remember being. The base, animal side of Sherlock Holmes wanted out of its cage to finish staking the claim on her body that it had already been started. He wanted to be inside her.

Her nipple was a stiff bud against his tongue, and he suckled her gently, first on one side, and then the other. Molly made soft nosies and squirmed against him. Her fingers were back in his hair, but tighter, demanding.

"_Harder,_" she whispered fiercely. _"Do it harder._"

Sherlock's groan rumbled in his chest, and he obliged, sucking hard, pulling her nipple deeper into his mouth and scraping his teeth gently across the sensitive tip. Molly's fingers dug hard into his scalp and her moan was loud and unrestrained.

At some point, she had wrapped her legs around his hips, but so lost in the taste and smell and feel of her, Sherlock hadn't even been aware of his body's instinctive reaction. He was moving rhythmically against her, but the awkward alignment of their bodies was all wrong for the pressure he craved.

He made a sound of frustration and reluctantly released her nipple so that he could bury his face in the sweet-smelling curve of her neck once more. He grabbed her hips and pulled her forward so that she was just barely balancing on the edge of the table, and then he held her there with his fingers digging into her, positioning her perfectly so that he could thrust hard against the warm apex of her thighs.

She gasped and he moaned, and Sherlock decided that the trousers needed to go.

He reached for the button, but she stopped him with her hand.

"No, Sherlock, don't."

He lifted his head and looked at her in bewildered confusion. "You want me to…stop?"

"Yes - or rather _no_," Molly let out a short huff of laughter. "No, I don't want you to stop, but I want - " She trailed off and reached for the buttons of his shirt. "It's only fair."

Relief crashed through him and he started to help her, but she batted his hand away.

"No. I'll do it."

Patiently as he could, Sherlock stood still and watched Molly make slow, methodical work of the buttons on his shirt.

"One," she said, and glanced up at him with a teasing smile. "Two - three - four - five." She stopped and spread the top part of his shirt open, and then leaned forward to press her lips against his breastbone.

He shuddered under her warm mouth. "Molly," he said, sounding strangled. "If you don't finish the job quickly, I'm going to do it myself, buttons be damned."

"Don't you dare," she said. "I like this shirt." Her hands returned to their work. "Six-seven-eight," she finished quickly, and then her hands were on his chest, pushing the dark fabric aside so that she could spread her fingers across his fair skin.

Her face was flushed and her eyes intent as she touched him. He might have expected her to be tentative and shy, but she was bold, sliding her palms across his stomach and then up over his ribs, slowing to let her thumbs catch on his nipples just as he had done to her.

He sucked in a shaky breath. "_Molly_," he said, but even he didn't know if it were in benediction or warning.

She smiled without looking up at him and tightened her legs around his hips. He bucked against her with a groan and her smile widened.

"_Molly_," he said again, and this time it was a warning. But she merely flicked a self-satisfied look at him and twitched her hips almost imperceptibly as she brushed her fingers across his nipples again.

"No more," he ground out and pulled away.

His hands went back to the button of her trousers, and this time she didn't try to stop him. He was beyond being gentle now, pulling them roughly over her hips and tossing them aside with the rest of her clothing.

When he turned back to her, his breath caught in his throat.

"Oh, God, Molly," he said in a hoarse whisper.

She was sitting on the table in the corner of the lab with her bare feet dangling off the floor, wearing nothing but pink panties that matched the bra that had somehow ended up hanging from the electron microscope on the next table over. Her hair was half undone, tendrils falling loose around her neck, and Sherlock was certain he had never seen anything more gloriously sensual in all his life.

Both of them were heavy-lidded and breathing hard. He felt a wave of smug satisfaction when he sank to his knees between her legs, and saw her eyes go wide as saucers.

He chuckled, letting his breath warm the inside of her bare thigh. "I did tell you that I meant to taste you. Didn't I?"

She managed a jerky nod, but that was all he saw before he directed his attention lower.

If he had found the the clean, fresh smell of Molly's skin appealing, the scent of her arousal could only be called intoxicating. It was musky and sweet and primal, and Sherlock was again shaken by the base urge to conquer her body with his own. This was the smell of sex, the wordless, primitive call to arms that he was all too happy to answer when it was Molly Hooper issuing the summons.

He wanted to taste her, was near desperate to put his mouth on her, but he also wanted to extend the anticipation a bit longer, to wallow in the poignant agony of an unfulfilled desire on the brink of being met.

Sherlock paid her back in full for her earlier teasing, brushing his lips slowly, so very slowly up the inside of her thigh from the patella to the femoral neck until his breath was hot and warm against the damp pink fabric that covered her sex.

Molly was gasping now, her entire body taut as a bowstring. "Sherlock!" she hissed and he smiled.

"Soon," he said, lowering his voice to a guttural rumble against the thin skin of her inner thigh.

The sound she made in response was equal parts desperate and frustrated and she squirmed against him, seeking out the contact that he was denying to her.

He moved closer, forcing her legs farther apart with his shoulders, and at last, so very gently, he nudged her with the bridge of his nose.

Molly's body went perfectly still.

He brushed his mouth over her, breathing warm against the slip of material that still hid her from him. With one hand he reached up and cupped the curve of her backside, holding her in place at the very edge of the table, and with the other he covered her centre and pressed gently. Molly's breath came out in a low moan and he felt a rush of wet warmth against his fingers.

A predatory smile crossed his face. The time for self-denial was over.

He reached up and hooked his fingers around the elastic band of her panties, sliding them down her legs with hands that shook in anticipation.

And then Molly Hooper was bared to him completely.

He looked up at her from his supplicating position, kneeling between her legs, and she was devastating.

Sherlock had been accused on more than one occasion of being unable to appreciate beauty when he saw it, but such was not actually the case. It was probably true that he did not value it in the same way as most people. A Botticelli or a Rembrandt hanging on a museum wall meant little to him, nor did the airbrushed, augmented-reality version of femininity that graced glossy magazine pages. He found beauty in the awesome, impossible order of the natural world - a clear night sky filled with a million million stars; the lacy, fernlike growth of ice crystals on a cold, winter window; the electrically charged particles that fell to earth as bright dancing lights over the poles - breathtaking, visual manifestations of scientific truth.

And now he looked up at the simple, human body of Molly Hooper - naked, flushed and panting down at him and she was, without a doubt, the most personally, achingly beautiful thing he had ever seen.

She was watching him with dazed eyes, her chest heaving, and he held her gaze until his mouth closed over her and his tongue found her centre. Then she moaned and Sherlock was lost to the thrill of discovery.

He had never tasted a woman this way before. It was an extraordinary flood of new sensations and he had to fight hard to slow the tide of sensory input lest it overwhelm him entirely. All he could hear and see and taste and smell and touch was _Molly_. His nose and chin and lips brushed short dark curls, damp with the evidence of her arousal, and she was hot and slick beneath his tongue. She tasted earthy and slightly sweet and nothing like what he had expected. He explored her with the focus of a scientist, mentally recording action and reaction until he was certain of what pleased her most and dedicated himself to eliciting the formless noises that she made as she pressed herself harder against his mouth.

His fingers dug into her thighs as he stroked her with long deliberate sweeps of his tongue. Her hands were tangled in his hair, her hips flexing instinctively toward him. He could feel her muscles tightening as she reached toward her completion.

"Sherlock!" Molly panted, her voice low and desperate. "_Please. Oh, please._"

He was only too ready to give her what she wanted. He wanted to see her - wanted to watch her face as she fell over the edge.

Without ever ceasing the slippery, sucking dance of his mouth on her sex he cast his eyes up and looked at her.

Molly's fair skin was flushed and and glowing, her breasts rising and falling with the rapid pace of her breathing. Her hair had finally come lose altogether and hung over her shoulders like a chestnut-colored curtain With her eyes closed and her lips parted, she looked wild and uninhibited. It required every ounce of self-control that Sherlock could muster not to abandon his work and take her _now_.

Instead he increased the pressure of his tongue, and slid one long finger inside her.

She cried out and bucked hard against him. Her face was etched with the pain of exquisite torture - her brow furrowed, her lips curled back from her teeth. She was on the edge - so close, _so very close_.

"Come for me, Molly," he rumbled against her tender flesh. He could feel her quickened response and the knowledge of her impending release thrilled through him. He would find her breaking point, know just how she felt and tasted, and how she sounded when she lost herself to the rush of endorphins that rolled over her in a tidal wave of pleasure. "Let me watch you come," he said, and then returned to the work of his lips and tongue and fingers, never taking his eyes off of her.

Almost immediately, he felt her fingers clench in his hair and her muscles tighten around him. Her panting breaths became short, staccato gasps and the blush on her cheeks deepened and spread down her throat and breasts. She shuddered and rocked against his mouth as he coaxed her gently through the waves of her orgasm. The cry that tore from her throat made Sherlock _proud_.

When the tremors passed and her body relaxed, she opened glittering eyes and looked down at him, panting breathlessly. He kissed her once more with a lingering pull of his lips that made her twitch and gasp. He smiled, a slow curvature of his lips, and she narrowed her eyes and reached for him.

He lunged to his feet and kissed her, hard, letting her taste herself on his tongue. Her lips were cold now and he warmed them with his own.

Molly's breasts were soft against his bare chest and his skin tingled under her touch. There was something unspeakably erotic about her tender nakedness, so vulnerable while he stood almost fully clothed in front of her. Part of him wondered if perhaps he wasn't the one that was most powerless, or for that matter, the most exposed.

One last vestige of the aloof reasoner remained somewhere deep in the recesses of his mind, reminding him of the need for detachment. If he stopped now, if he released his hold on Molly and backed away from her at once, he could still pretend disinterest. He might still be able to convince himself that he was no more than a distant observer, motivated only by curiosity that demanded experimentation. He could still walk away no worse for the wear for having indulged in his desire to discover new things about Molly Hooper.

Except that it had been too late for that since the moment his lips first brushed that perfect spot on her neck. This was an experiment into the breaking point of Sherlock Holmes, and it had been from the very beginning.

And now her nimble fingers were on the button of his trousers and he knew he was well and truly lost.

She made short work of button and zip, never pulling her lips away from his, and then her small hand was on him. He groaned into her mouth, and her fingers tightened gently. He pressed himself into her, glorying in her soft touch, but wanting so much more.

Molly freed him from his pants and trousers, doing little more than shoving the impeding fabric out of the way in her haste. She stroked the smooth, hot flesh, and his cock jumped eagerly in her hand.

Sherlock's lips hovered over Molly's, their breath mingling, but his eyes were closed and the only attention he could spare was for the gentle glide of her fingers.

"Molly," he whispered into her mouth. He was desperate now, shaking with a physical need he hadn't known since the dark days of his addiction.

Her hand fell away and he felt a jolt at the loss, but then her legs went around him, and tightened, pulling him into the hot, sweet space between her legs. He moaned and leaned into her, pressing his forehead against hers and letting their lips brush together.

"Sherlock," she said softly and tilted her hips in invitation.

"Oh, God, _Molly_," he said and slid hard into her with a single thrust.

Molly arched her back, and gasped.

His mind and body and heart were overwhelmed by the pure pleasure of her body, hot and wet and wrapped tight around him. He moaned and moved inside her, his hands gripping her bare hips with bruising force.

As an experiment, it was a failure. He had not, _could not_, stay unbiased. The results were coloured by his own desires, control of the conditions lost before he had taken the first step towards testing a hypothesis he already knew to be true. He could no longer delude himself into believing that he was merely an impartial observer, that he was disconnected and free from the prejudices of human passion.

He gloried in the abandon of his reserve and threw himself willingly over the precipice where sex was was no longer a mere physiological imperative, and was instead an expression of _everything_. In this moment, her soft skin, grasping heat and gentle cries were all that mattered or ever would matter. He buried himself in her and withdrew, groaning into the damp hollow of her throat.

Molly's voice spoke sweet, breathless words into his ear that his heart heard, even if his mind did not process them. Her arms were locked around his neck, her cheek pressed to his as she braced herself against the force of his thrusts.

"Molly"", he said, almost mindless with the need that rose in him like the tide. "Molly, Molly!"

Molly's voice was a breathy hiss. "Sherlock!" He felt her legs tighten around him and her hips flex, and then she was pulsing around him again, crying out her completion. This time, he went with her. With a cry of his own, he thrust into her one last time and then froze, shaking as he spilled himself inside her.

For a long, drawn out moment all thought and reason were obliterated by waves of intense physical pleasure, and Sherlock Holmes was like any other man, consumed by the pure, carnal satisfaction of the body.

He came slowly back to himself, still pressed hard against Molly, their chests rising and falling in time as their breathing gradually returned to normal.

A dangerous experiment, certainly - with explosive results, most definitely.

And now his curiosity should be sated, his desire to know should be satisfied. The mercurial mind of Sherlock Holmes should be cataloguing and classifying this new sensory information - filing it away as data, and then turning, without a backward glance, to the next unknown.

But it wasn't - he wasn't.

Even while the flood of neurochemicals was still coursing through his body, even while he was still inside her, he wanted to know _more_. Even with every facet of sexual satiety already achieved, he still wanted her. Curiosity beget curiosity. And as he stood there with his hands and body still molded tight against her, Sherlock couldn't help but wonder if he would ever know enough about her to satisfy him.

It was Molly who moved first, lifting her forehead from his shoulder. But her eyes were downcast, as if she didn't want to meet his gaze. "Um, I guess I should just -"

Sherlock stopped her from pulling away with a gentle hand against her cheek. "Surely you don't think I am done being curious about you yet, Molly Hooper?"

She flashed him an uncertain smile. "I'm really not that interesting, Sherlock."

He chuckled. "I beg to differ. I think there's still quite a lot left for me to discover about you." He kissed her lips again, softly. "Perhaps tomorrow evening you'll come to Baker Street for dinner, and then allow me to indulge my curiosity a bit more?"

"Dinner?" Molly said. "With you?"

"Despite popular misconception, I do in fact eat," he replied with with a wry twist of his lips. "Yes, dinner, with me, at Baker Street, tomorrow night. Will you come?"

"So, you - you want to do this - something like this - again?"

Sherlock's full lips curled up into a long, slow smile. "Oh, yes. Many times."

Her nod was mildly dazed. "Oh, well, okay then."

"Excellent!" he said, and then kissed her again, harder - a lingering promissory note that he fully intended to cash in once he'd gotten her alone in his flat.

He couldn't say exactly what would happen tomorrow night. He wasn't even entirely sure he could provide anything in the way of a dinner without first consulting with Mrs. Hudson. But he did know that for an experiment to be truly successful, the results must be repeatable.

And Sherlock Holmes was _curious._

* * *

A/N: This was written in response to the '50 Reasons to Have (Sherlolly) Sex' smut prompt over on Tumblr. My reason was 'curiosity', and what could be more Holmesian than *that*?__

Posting unbetaed and unBrit-picked.


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